348 lines
13 KiB
C
348 lines
13 KiB
C
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// BSD 3-Clause License
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//
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// Copyright (c) 2021, Aaron Giles
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice, this
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// list of conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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//
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// 3. Neither the name of the copyright holder nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef YMFM_PCM_H
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#define YMFM_PCM_H
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#pragma once
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#include "ymfm.h"
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namespace ymfm
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{
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/*
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Note to self: Sega "Multi-PCM" is almost identical to this
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28 channels
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Writes:
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00 = data reg, causes write
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01 = target slot = data - (data / 8)
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02 = address (clamped to 7)
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Slot data (registers with ADSR/KSR seem to be inaccessible):
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0: xxxx---- panpot
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1: xxxxxxxx wavetable low
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2: xxxxxx-- pitch low
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-------x wavetable high
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3: xxxx---- octave
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----xxxx pitch hi
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4: x------- key on
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5: xxxxxxx- total level
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-------x level direct (0=interpolate)
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6: --xxx--- LFO frequency
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-----xxx PM sensitivity
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7: -----xxx AM sensitivity
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Sample data:
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+00: start hi
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+01: start mid
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+02: start low
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+03: loop hi
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+04: loop low
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+05: -end hi
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+06: -end low
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+07: vibrato (reg 6)
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+08: attack/decay
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+09: sustain level/rate
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+0A: ksr/release
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+0B: LFO amplitude (reg 7)
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*/
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//*********************************************************
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// INTERFACE CLASSES
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//*********************************************************
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class pcm_engine;
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// ======================> pcm_cache
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// this class holds data that is computed once at the start of clocking
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// and remains static during subsequent sound generation
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struct pcm_cache
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{
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uint32_t step; // sample position step, as a .16 value
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uint32_t total_level; // target total level, as a .10 value
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uint32_t pan_left; // left panning attenuation
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uint32_t pan_right; // right panning attenuation
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uint32_t eg_sustain; // sustain level, shifted up to envelope values
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uint8_t eg_rate[EG_STATES]; // envelope rate, including KSR
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uint8_t lfo_step; // stepping value for LFO
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uint8_t am_depth; // scale value for AM LFO
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uint8_t pm_depth; // scale value for PM LFO
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};
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// ======================> pcm_registers
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//
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// PCM register map:
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//
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// System-wide registers:
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// 00-01 xxxxxxxx LSI Test
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// 02 -------x Memory access mode (0=sound gen, 1=read/write)
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// ------x- Memory type (0=ROM, 1=ROM+SRAM)
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// ---xxx-- Wave table header
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// xxx----- Device ID (=1 for YMF278B)
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// 03 --xxxxxx Memory address high
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// 04 xxxxxxxx Memory address mid
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// 05 xxxxxxxx Memory address low
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// 06 xxxxxxxx Memory data
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// F8 --xxx--- Mix control (FM_R)
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// -----xxx Mix control (FM_L)
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// F9 --xxx--- Mix control (PCM_R)
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// -----xxx Mix control (PCM_L)
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//
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// Channel-specific registers:
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// 08-1F xxxxxxxx Wave table number low
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// 20-37 -------x Wave table number high
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// xxxxxxx- F-number low
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// 38-4F -----xxx F-number high
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// ----x--- Pseudo-reverb
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// xxxx---- Octave
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// 50-67 xxxxxxx- Total level
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// -------x Level direct
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// 68-7F x------- Key on
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// -x------ Damp
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// --x----- LFO reset
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// ---x---- Output channel
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// ----xxxx Panpot
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// 80-97 --xxx--- LFO speed
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// -----xxx Vibrato
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// 98-AF xxxx---- Attack rate
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// ----xxxx Decay rate
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// B0-C7 xxxx---- Sustain level
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// ----xxxx Sustain rate
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// C8-DF xxxx---- Rate correction
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// ----xxxx Release rate
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// E0-F7 -----xxx AM depth
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class pcm_registers
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{
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public:
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// constants
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static constexpr uint32_t OUTPUTS = 4;
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static constexpr uint32_t CHANNELS = 24;
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static constexpr uint32_t REGISTERS = 0x100;
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static constexpr uint32_t ALL_CHANNELS = (1 << CHANNELS) - 1;
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// constructor
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pcm_registers() { }
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// save/restore
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void save_restore(ymfm_saved_state &state);
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// reset to initial state
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void reset();
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// update cache information
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void cache_channel_data(uint32_t choffs, pcm_cache &cache);
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// direct read/write access
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uint8_t read(uint32_t index ) { return m_regdata[index]; }
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void write(uint32_t index, uint8_t data) { m_regdata[index] = data; }
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// system-wide registers
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uint32_t memory_access_mode() const { return bitfield(m_regdata[0x02], 0); }
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uint32_t memory_type() const { return bitfield(m_regdata[0x02], 1); }
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uint32_t wave_table_header() const { return bitfield(m_regdata[0x02], 2, 3); }
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uint32_t device_id() const { return bitfield(m_regdata[0x02], 5, 3); }
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uint32_t memory_address() const { return (bitfield(m_regdata[0x03], 0, 6) << 16) | (m_regdata[0x04] << 8) | m_regdata[0x05]; }
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uint32_t memory_data() const { return m_regdata[0x06]; }
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uint32_t mix_fm_r() const { return bitfield(m_regdata[0xf8], 3, 3); }
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uint32_t mix_fm_l() const { return bitfield(m_regdata[0xf8], 0, 3); }
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uint32_t mix_pcm_r() const { return bitfield(m_regdata[0xf9], 3, 3); }
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uint32_t mix_pcm_l() const { return bitfield(m_regdata[0xf9], 0, 3); }
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// per-channel registers
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uint32_t ch_wave_table_num(uint32_t choffs) const { return m_regdata[choffs + 0x08] | (bitfield(m_regdata[choffs + 0x20], 0) << 8); }
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uint32_t ch_fnumber(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x20], 1, 7) | (bitfield(m_regdata[choffs + 0x38], 0, 3) << 7); }
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uint32_t ch_pseudo_reverb(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x38], 3); }
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uint32_t ch_octave(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x38], 4, 4); }
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uint32_t ch_total_level(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x50], 1, 7); }
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uint32_t ch_level_direct(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x50], 0); }
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uint32_t ch_keyon(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x68], 7); }
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uint32_t ch_damp(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x68], 6); }
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uint32_t ch_lfo_reset(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x68], 5); }
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uint32_t ch_output_channel(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x68], 4); }
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uint32_t ch_panpot(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x68], 0, 4); }
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uint32_t ch_lfo_speed(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x80], 3, 3); }
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uint32_t ch_vibrato(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x80], 0, 3); }
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uint32_t ch_attack_rate(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x98], 4, 4); }
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uint32_t ch_decay_rate(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0x98], 0, 4); }
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uint32_t ch_sustain_level(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0xb0], 4, 4); }
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uint32_t ch_sustain_rate(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0xb0], 0, 4); }
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uint32_t ch_rate_correction(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0xc8], 4, 4); }
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uint32_t ch_release_rate(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0xc8], 0, 4); }
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uint32_t ch_am_depth(uint32_t choffs) const { return bitfield(m_regdata[choffs + 0xe0], 0, 3); }
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// return the memory address and increment it
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uint32_t memory_address_autoinc()
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{
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uint32_t result = memory_address();
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uint32_t newval = result + 1;
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m_regdata[0x05] = newval >> 0;
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m_regdata[0x04] = newval >> 8;
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m_regdata[0x03] = (newval >> 16) & 0x3f;
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return result;
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}
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private:
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// internal helpers
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uint32_t effective_rate(uint32_t raw, uint32_t correction);
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// internal state
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uint8_t m_regdata[REGISTERS]; // register data
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};
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// ======================> pcm_channel
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class pcm_channel
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{
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static constexpr uint8_t KEY_ON = 0x01;
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static constexpr uint8_t KEY_PENDING_ON = 0x02;
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static constexpr uint8_t KEY_PENDING = 0x04;
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// "quiet" value, used to optimize when we can skip doing working
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static constexpr uint32_t EG_QUIET = 0x200;
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public:
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using output_data = ymfm_output<pcm_registers::OUTPUTS>;
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// constructor
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pcm_channel(pcm_engine &owner, uint32_t choffs);
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// save/restore
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void save_restore(ymfm_saved_state &state);
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// reset the channel state
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void reset();
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// return the channel offset
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uint32_t choffs() const { return m_choffs; }
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// prepare prior to clocking
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bool prepare();
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// master clocking function
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void clock(uint32_t env_counter);
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// return the computed output value, with panning applied
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void output(output_data &output) const;
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// signal key on/off
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void keyonoff(bool on);
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// load a new wavetable entry
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void load_wavetable();
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private:
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// internal helpers
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void start_attack();
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void start_release();
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void clock_envelope(uint32_t env_counter);
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int16_t fetch_sample() const;
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uint8_t read_pcm(uint32_t address) const;
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// internal state
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uint32_t const m_choffs; // channel offset
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uint32_t m_baseaddr; // base address
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uint32_t m_endpos; // ending position
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uint32_t m_looppos; // loop position
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uint32_t m_curpos; // current position
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uint32_t m_nextpos; // next position
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uint32_t m_lfo_counter; // LFO counter
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envelope_state m_eg_state; // envelope state
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uint16_t m_env_attenuation; // computed envelope attenuation
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uint32_t m_total_level; // total level with as 7.10 for interp
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uint8_t m_format; // sample format
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uint8_t m_key_state; // current key state
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pcm_cache m_cache; // cached data
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pcm_registers &m_regs; // reference to registers
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pcm_engine &m_owner; // reference to our owner
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};
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// ======================> pcm_engine
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class pcm_engine
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{
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public:
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static constexpr int OUTPUTS = pcm_registers::OUTPUTS;
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static constexpr int CHANNELS = pcm_registers::CHANNELS;
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static constexpr uint32_t ALL_CHANNELS = pcm_registers::ALL_CHANNELS;
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using output_data = pcm_channel::output_data;
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// constructor
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pcm_engine(ymfm_interface &intf);
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// reset our status
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void reset();
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// save/restore
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void save_restore(ymfm_saved_state &state);
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// master clocking function
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void clock(uint32_t chanmask);
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// compute sum of channel outputs
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void output(output_data &output, uint32_t chanmask);
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// read from the PCM registers
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uint8_t read(uint32_t regnum);
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// write to the PCM registers
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void write(uint32_t regnum, uint8_t data);
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// return a reference to our interface
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ymfm_interface &intf() { return m_intf; }
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// return a reference to our registers
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pcm_registers ®s() { return m_regs; }
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private:
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// internal state
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ymfm_interface &m_intf; // reference to the interface
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uint32_t m_env_counter; // envelope counter
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uint32_t m_modified_channels; // bitmask of modified channels
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uint32_t m_active_channels; // bitmask of active channels
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uint32_t m_prepare_count; // counter to do periodic prepare sweeps
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std::unique_ptr<pcm_channel> m_channel[CHANNELS]; // array of channels
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pcm_registers m_regs; // registers
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};
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}
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#endif // YMFM_PCM_H
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